Social distancing is very costly to our society and not everyone needs to be doing it. The greater Seattle area alone is right now rapidly filling up with many thousands of people who have already gotten over the COVID-19 “Chinese coronavirus” and are thus not at significant risk either of catching this disease again or of passing it on. We just need to make it easy for people to discover their already-had-it status. Then as long as they wash their hands they should be out engaging in the public activities that keep our economy and our society going.

The nationwide rollout of drive-thru testing for active coronavirus infection is starting to identify some of the immune population. Almost all of those who test positive will within a couple of weeks be well over their symptoms and no longer able transmit the disease. But active virus testing by itself will leave the biggest part of the immune population unidentified.

First it can’t identify anybody who is already over the disease, which means anybody who caught Corona more than two weeks ago. With the highly contagious “Wuhan flu” circulating since at least mid-January those numbers could be large and the people affected are the ones who can be stepping out to keep our economy running right now.

Going forward the live virus test will continue to miss most infections. Current estimates are that about half of the Corona infections are asymptomatic, or nearly so. In the words of Doctor Marty Makary of Johns Hopkins (at 1:10 here):

We do know, if we look at the Diamond Princess and other examples, that about half of people probably have no symptoms or mild symptoms.

The silent spread of “Kung Flu” (the moniker popularized by CBS reporter Weijia Jiang) will be and probably already has been vast. The only way to identify the large and important group of people who have been part of this expanding wave is to have a nationwide roll-out of antibody testing to anybody who wants it, a rollout on the same scale as the live virus testing.

Given the important social benefits we shouldn’t charge for it and we should try hard to really sell people on the personal benefits:

“Hear ye, hear ye! Get you antibody check here! If you’ve already got Corona antibodies then you’ve have a “get out of social-distance-jail free” card. Go out dancing! Go to the movies! Go to the restaurant! And most importantly, go back to work.”

Add antibody testing to drive through PCR and encourage everybody to do both

The active virus test uses polymerase chain reaction testing (PCR) on nasal and throat swabs to look for the RNA of the Chinese Coronavirus. Antibody tests require a blood sample but are already available and, like the PCR tests, return results in a few hours. Everybody who does one should probably also get the other.

Why? Because people whose current symptoms turn out to be an ordinary flu might nevertheless have already gotten over Corona so they should test for that too, even if they have no awareness of an earlier infection. Similarly, currently symptomless people who want to find out if they already had Corona might turn out to have an active infection.

The large social benefits of each say to do both and Biomedomics says that their rapid antibody test only requires a finger-prick blood sample so it could probably be done drive-through at the same time as the swab testing.

As Corona comes to look less dangerous our response is becoming more extreme

The news from the frontlines of the Corona War looks good. We already have strong indications of about 1% mortality from the Diamond Princess and from South Korea. That’s high for an ordinary flu but there has also been great progress in finding effectiveremedies that could reduce the mortality by quite a bit. Then there is the high estimated proportion of asymptomatic cases. If borne out that will not only keep the Coronavirus mortality rate low but it will also mean that we already have a good start on herd immunity.

Logically it seems that we are not far from the point where we can declare the situation manageable and start rolling back the extremes of social distancing and economic shutdown that are now in place. We shouldn’t be in too much of a hurry. The domestic testing data is finally starting to roll in and we need to look at it, but if we can get to the point where the risks can placed in the ballpark of an ordinary-flu (or a modest multiple of an ordinary flu) then we should drop all but the most basic social distancing (stay home when sick), and stop incurring the serious economic harm that more drastic social distancing is already starting to cause. Nothing kills as many people as poverty and even a modest recession upends the lives of those who end up without work.

But while the news from the war front is good multiple levels of government are forging full speed ahead with even more drastic distancing and shut-down. Multiplestates have already committed to shutting down the rest of their public school years, California just locked all of its 40 million citizens in their houses and PA shut down its highway rest stops! (Now they are only shutting down the bathrooms, yay. One cheer.)

It goes on and on in a mad rush. A trillion dollar stimulus package is in the works and Congress is looking to enact responses into law. Radical shut down plans are being floated from sources one would expect to be rational (MITRE), going far beyond the original stated goal of trying to slow the spread of the Coronavirus and instead explicitly advocating efforts to stopping Corona from spreading at all.

To defeat Corona, we can’t let our own immune system kill us

If the medical test data now coming in reveals some terrible bad news then a prolonged social distancing response could still turn out to be right, but people being people, extreme distancing could continue even if it is terribly wrong.

Remember how the Coronavirus kills (in the rare cases where it does kill): by provoking an over-reaction from the host body’s immune system that attacks and destroys the host’s own cells. That is exactly what our current “immune response” of shutting down the economy will quickly achieve if we follow it very long, whether on solid grounds or in terrible error.

The only way to survive going much further down this road is with mass antibody testing that releases those who have gotten over the Coronavirus from further social distancing. If we are going to take this very dire economy-ravaging medicine, akin to subjecting the body to a 106° fever, it is crucial that we mitigate the harm by exempting those for whom it is completely unnecessary.

Those people are going to be our skeleton crews and their unconstrained mobility is going to be most important when we are at our lowest point. As their numbers grow they are going to pave our road back. They are going to be our road back.

Eventually we will all be there. A year or two from now when effective vaccines are finally available we will all have immunity. But a year is a very long time to be flat on our back economically. In the meantime we need the growing army of our immune countrymen to be our legs and we need to take steps to get those legs up and under us.

So long as we are even contemplating continued social distancing it is imperative that we put mass antibody testing right at the top of our priority list. We desperately need protection not just from the Coronavirus but also from the immune response that our society implements to attack the virus, or it won’t just get a few of us. It will get all of us.

Does the possibility of reinfection change this analysis?

Reinfection would seem to be a second order concern but it is something we need to investigate. Flus always mutate, eventually coming back different enough to strike again. By then we should not only have vaccines but our vaccine industry should be developing vaccines much quicker than in the past, a change that is already emerging.

As for reinfection by a single strain, that should not happen with a healthy immune system and probably hasn’t happened. “If this acts like any other virus, once you recover, you won’t get reinfected,” says Anthony Fauci, director of the National Institute of Allergy and Infectious Disease, and there are other possible explanations for the few seeming cases of reinfection, such as incomplete recovery and tests that missed the still infected body parts.

But we do know of one possible danger on the multiple-strain front already. Chinese researchers say that they have identified two major strains, a more aggressive “L” strain that was predominant in Wuhan but has since lost ground to a less aggressive “S” strain.

The small number of known cases of seeming reinfection suggest that there must be strong cross-immunity between whatever different strains exist, but what if that is not the explanation? Could the reason we aren’t seeing reinfection across the L and S strains be that they travelled off in different directions?

Plausible or not, just take it as a worst case example where we would be forced to deal with in-effect two different flus at once. Would it change our fundamental strategy? No. Mass antibody testing would still be a top priority.

If both flus were beyond containment we would have to double all the testing, doing mass PCR tests and mass antibody tests for both viruses. Higher mortality and less immunity would make more social distancing necessary, which would impose more economic damage, making it all the more important to identify those people who don’t need to social distance.

The difference is that they would have to be immune to both strains, which means there would be far fewer of them, which would make them that much more valuable. The shorter the supply of an economic input the higher its marginal productivity. The first glass of water in the desert is the most important.

The already immune are still going to have to fill crucial points of human contact so the fewer there are of them the more important finding them becomes. Thus under all scenarios, until we decide that social distancing is no longer necessary, antibody testing will be a crucial tool for limiting the economic and social damage that social distancing inflicts.